1 /*
2 * ====================================================
3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
4 *
5 * Developed at SunPro, a Sun Microsystems, Inc. business.
6 * Permission to use, copy, modify, and distribute this
7 * software is freely granted, provided that this notice
8 * is preserved.
9 * ====================================================
10 */
11
12 /*
13 * truncf(x)
14 * Return x rounded toward 0 to integral value
15 * Method:
16 * Bit twiddling.
17 * Exception:
18 * Inexact flag raised if x not equal to truncf(x).
19 */
20
21 #include "math.h"
22 #include "math_private.h"
23
24 static const float huge = 1.0e30F;
25
26 float
truncf(float x)27 truncf(float x)
28 {
29 int32_t i0,j0;
30 u_int32_t i;
31 GET_FLOAT_WORD(i0,x);
32 j0 = ((i0>>23)&0xff)-0x7f;
33 if(j0<23) {
34 if(j0<0) { /* raise inexact if x != 0 */
35 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */
36 i0 &= 0x80000000;
37 } else {
38 i = (0x007fffff)>>j0;
39 if((i0&i)==0) return x; /* x is integral */
40 if(huge+x>0.0F) /* raise inexact flag */
41 i0 &= (~i);
42 }
43 } else {
44 if(j0==0x80) return x+x; /* inf or NaN */
45 else return x; /* x is integral */
46 }
47 SET_FLOAT_WORD(x,i0);
48 return x;
49 }
50